code: def center_distance(self, bubble, bubbles):
      return np.hypot(
          bubble[0] - bubbles[:, 0], bubble[1] - bubbles[:, 1]
      )
  
file_path: matplotlib/galleries/examples/misc/packed_bubbles.py
imports: import matplotlib.pyplot
  import numpy
label_desc: Use image node_id 3 for calling the BubbleChart obj's underlying member method code with example usage: obj.center_distance(bubble, bubbles) and returns: np